1. Field of Invention
This invention relates to Photovoltaic Roof Panels and Flashing, Specifically to integration into asphalt roof systems.
2. Background of the Invention
Photovoltaic manufactures have made solar cells capable of generating electricity, but have not provided the means of mounting these Photovoltaic cells to structures in a manner that meet building code standards. Building codes that have been developed to be used together set forth for strength design, fire prevention and weather protection.
The Thin Film Amorphous photovoltaic manufactures have designed PV cells to be adhered to metal and rubber membranes used in manufacturing roofing materials. Leaving designers to develop a product made of these materials that meet the building codes. Limiting their use to roofs, that all ready uses these roofing systems and fit the criteria of mounting the PV cells or new products developed to merge the Photovoltaic and roofing material. Adhering PV Laminates directly to existing roof systems makes it hard or impossible to service the photovoltaic system, and the roof system without total replacement of each system. If a photovoltaic cells on one roof panel goes bad and quits producing electricity at an acceptable rate it will degrade the power of several panels connected to that series. This will drastically reduce the output of the whole system. The wiring together of these PV cells is critical in the system design. For optimal performance of the photovoltaic system, you need to be able to replace bad or low efficiency photovoltaic cells, in the same physical location for wiring logistics. You can't just bypass a bad photovoltaic roof panels in wiring, without rewiring the complete system to even out the number of cells in each series.
Peeling off the photovoltaic cells from the panel in a manner to reuse the metal panel isn't really possible. Removing a standard metal roof panel with concealed fasteners is not cost effective and often you need to remove several panels to replace one.
Exposed fastener roof panels are designed with multiple structural ribs and don't have enough room between the ribs for existing thin film amorphous photovoltaic cells. If the manufacture custom made them to fit an existing exposed fastener panel you would still have three separate sets of cells on one panel and would have to replace all three if one goes bad.
Most existing metal roof panels with concealed fasteners and exposed fastener have small stiffening ribs between the large structural ribs that won't allow for proper adhesion for the thin film amorphous cells. So installing the cells to nearly all existing metal roof is not practical.
Current metal roof panels don't allow for installation and removal of PV panels horizontally and vertically on the roof.
Current installations of photovoltaic system over the top off existing roofing, requires an engineer to recertify the rafters that support the roof. The rafter must be able to handle the extra weight of the photovoltaic system.
Current fire codes require a path to the ridge without having the firefighter cross over photovoltaic systems. These new codes require easement along the rakes, valleys and ridge of the roof. It's standard firefighter practice to make a hole in the ridge, to release dangerous gases. The firefighter cannot cut through or walk on a photovoltaic system because of electrocution dangers.